Liquid fuel pump



Oct. 2, 1956 G. J. GERMANN LIQUID FUEL PUMP 5 Sheefs-Sheet 1 Filed March 10, 1952 INVENTOR.

. GEORGE J.GERMANN Wm W-M ATTORNEYS Oct. 2, 1956 G. J. GERMANN 2,764,947

LIQUID FUEL PUMP Filed March 10, 1952 3 Sheets-Sheet 2 INVENTOR. GEORGE J. GERMANN BY WWW ATTORNEYS Oct. 2, 1956 G. J. GERMANN 2,764,947

LIQUID FUEL PUMP Filed March 10, 1952 3 Sheets-Sheet 3 INVENTOR.

GEORGE J GERMANN ATTORNEYS United States Patent Mich., assignor to Auto- Mich., a corporation of The invention relates to liquid fuel pumps more particularly designed for use on motor vehicles for elevating the fuel from the storage tank to the carburetor and the type electromagnetically operated.

It is one of the objects of the invention to obtain a smooth flow of the fluid column, avoiding pulses or shocks incident to the intermittent actuation of the motor.

It is a further object of the invention to obtain a simple, relatively inexpensive construction having a minimum of separate parts and One occupying relatively small space in comparison to the volume of fluid which it handles.

It is a further object to obtain a construction in which the elements of the mechanism are easily assembled and are readily accessible for adjustment or repair.

With these objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Figure l is a side elevation of the motor pump;

Figure 2 is a plan view thereof with the cover removed;

Figure 3 is a bottom plan view of the removed cover and elements carried thereby;

Figure 4 is a top plan view thereof;

Figure 5 is a bottom plan view of the motor pump;

Figure 6 is a section on line 6-6, Figure 5;

Figure 7 is a section on line 7-7, Figure 6;

Figure 8 is a section on line 8-8, Figure 5;

Figure 9 is a section on line 9-9, Figure 5.

Generally described the pump comprises a casing having a liquid fuel-holding chamber therein with valve controlled inlet and outlet passages, reciprocatory displacement means arranged in connection with said chamber and an electromagnetic reciprocatory motor for actuating said displacement means to alternately draw fluid into and expel it from said chamber through said connections. With the construction as thus far described the operation of the displacement means by the motor would cause a jerky action which would be communicated to the liquid being pumped. This would occur in both the inlet and outlet passages and the conduits connected therewith. I have therefore provided cushioning means which, while permitting rapid displacement of a small volume of liquid, will impart a more gradual flow through the connecting conduits. Such means comprises essentially sealed air cushion chambers connected respectively to the inlet and outlet passages and of a volume not greatly exceeding the maximum volume displaced by said displacement means in a single stroke thereof, also separating means between the air and liquid (preferably a flexible corrugated diaphragm) placed in each of said air chambers. Thus upon the suction stroke of the displacement means the air in the chamber connected with the inlet will expand while upon the pressure stroke of the displacement means the air in the chamber connected with the outlet will be compressed. This will avoid instantaneous or rapid displacement of the liquid in the connections but in each case by creating differential air pressures will store energy for effecting the more gradual flow of the liquid through said connections.

2,764,947 Patented Oct. 2, 1956 ice Casing In the specific construction illustrated and described, the housing of the motor pump is chiefly formed of a single integral element A, preferably a die casting. The upper portion of the element A has a chamber B formed therein which is open at the top and contains the movable elements of the mechanism. The bottom of this chamber has a comparatively shallow cylindrical recess C therein which in turn has formed in the bottom thereof a pair of small diameter recesses D and E. Below the chamber portion of the casing A is an integral portion A having therein a cylindrical chamber F open at the bottom, coaxial and communicating with the recess D. There is also a horizontally extending passage G which intersects the chamber F and extends out from the casing. A second horizontal passage H extends beneath the recess E and is in communication therewith. One end of this passage opens through the side face of the portion A, while at the opposite end of the passage is an enlarged diameter portion H which opens through the opposite side face. All of these chambers and passages are formed in the casing during the casting thereof I is a closure member for the chamber B which is secured to the top of the member A. J is a hollow cap member forming a closure for the chamber F and K is a similar hollow cap member for closing the end of the enlarged portion H of the passage H. These elements together with the element A constitue the entire housing of the motor pump.

Pump construction Extending over the cylindrical recess C is a flexible diaphragm L which is marginally clamped to the bottom of the chamber B by a hollow annular member M. This member is preferably formed of pressed sheet metal and has an outer flange M for clamping the diaphragm and an upwardly extending conical portion M terminating in an inner return bend portion M The diaphragm L has plates L and L above and below the same and extending over the central portion thereof. The peripheral portions of these plates are rounded for bearing against the adjacent outer portion of the diaphragm without'injury thereto. The plates are secured to each other by a central member N having on the head portion thereof stepped bearings for the plates and also a threaded shank N engaged by a clamping nut N This imparts comparative rigidity to the central portion of the diaphragm while leaving a flexible annular portion surrounding the plates L, L between the same and the clamped marginal portion of the diaphragm. Housed within the annular member M is a coil spring 0, which at its outer end abuts against the return bent portion M while its inner end bears against the plate L. The spring is of sufiicient length to be compressed when the member M is secured to the bottom of the chamber by clamping screws M thereby pressing the diaphragm L downward into the recess C. The amount of this movement is however limited by the striking of the head of the member N against the bottom of the recess C. The valves controlling inlet and outlet of fluid from the recess C are located in the small diameter recesses D and E. The valve P located in the recess D controls the inlet of fluid from the passage G and chamber F, and the valve P in the recess E controls outlet of fluid from the recess C. The seat P with the valve P is at the bottom of the recess surrounding the port which communicates with the chamber F. An annular member P pressed into the upper end of the recess D forms an abutment for a spring P which yieldably holds the valve P to its seat. The valve P is seated on an annular member P similar to the member P and pressed into the upper end of the recess E, and a spring P abutting against the lower end of the recess yieldably holds this valve to its seat.

Motor construction An electromagnetic motor is employed for actuating the diaphragm L in an upward direction against the resistance of the spring and for simultaneously storing additional energy in said spring for actuating the diaphragm in a downward direction. This motor comprises an electromagnet preferably housed in an upwardly cupped portion I of the closure I and which includes a central core member Q of magnetic material having a shouldered engagement with the portion I and secured by an outer plate Q and Q An electric coil Q surrounds the core and is housed in the annular space between the same and the wall of the cup. The lower face of the core member constitutes one pole of the magnet and the plate I together with the cup I, which are also formed of magnetic material, form a surrounding unlike pole of the magnet. The armature R for the magnet is arranged within the chamber B and is mounted upon the member A. The mounting comprises a strap member R which is secured by screws R to corner post portions A within the chamber B but of lesser height. Depending from this strap are posts formed by screws R with heads at the lower end thereof and sleeves between said heads and the strap. The armature is formed by a plurality of superposed plates secured to each other and certain of these plates extend beneath said strap and are apertured to loosely fit about said posts. Coil springs surrounding the posts yieldably press said plates upward against the strap but permit a limited angular or hinge movement of the armature with respect to said posts and strap. The screws R also form a mounting for a thin resilient plate S which is electrically insulated by insulator members S above and below the same clamped between the heads of the screws and the sleeves thereon. The plate S is thus held normally parallel to the armature R but spaced and insulated therefrom. A pair of contact members S are secured to the free end of the plate S and are in registration with but normally spaced from cooperating contact members S on the underside of the armature plate. A second armature S i mounted on the plate S and extends through an aperture in the armature R into proximity to the central pole of the magnet. A member S of non-magnetic material is secured to the armature S and a forward extension R from the strap R extends into the path of the member S to arrest movement of the armature S- towards the pole of the magnet in advance of the termination of movement of the armature R. One of the superposed plates of the armature has a forward bifurcated hooked extension R at its free end which engages a cross-pin T on a connecting rod T threadedly engaged with the member N. The circuit (not shown) for the electromagnet includes a circuit breaker formed by the cooperating contacts S and S and also includes the contact members S and S respectively on the closure I and plate S, which are in contact when said plate is mounted on the casing A. The armature R is drawn downward by the spring 0 so as to close with each other the contacts 8 and S thereby closing the electrical circuit and energizing the magnet. The magnetic pull on the armature S maintains these contacts together during the upward movement of the armature R until the stop R arrests further movement of the armature S and plate S causing separation of the contacts S from the contacts 8 This will tie-energize the magnet and permit the spring to return the armature to a position where said contacts S and S are again pressed together. Thus the diaphragm L will be alternately raised and lowered to respectively draw the liquid fuel into the recess C past the inlet valve P and to expel it from said recess past the outlet valve P.

With the construction as thus far described, the pumping of the liquid fuel would be accomplished but with a jerky action. This is due to the fact that the actuation of the armature under magnetic pull is almost instantaneous, whereas the movement of the liquid is necessarily slower due to its inertia. To smooth out the pumping action, I have devised a construction in which only a small volume of the liquid will be directly moved by the diaphragm permitting the larger volume to move more slowly, the construction being as follows. it has been stated that the hollow caps I and K respectively close the chamber F of the inlet passage and the enlarged portion H of the outlet passage. These caps also serve to clamp in position corrugated flexible diaphragms U and V which separate the liquid in the passage from air within the cap. Thus in each cap there is air originally at atmospheric pressure but further compressed by any excess pressure in the liquid on the opposite side of the diaphragm. If the pressure on the liquid is diminished to less than atmospheric pressure the air within the cap will expand and move the diaphragm to displace the liquid. On the other hand, if the pressure of the liquid is increased, the diaphragm will be moved outward compressing the air in the hollow cap to an equal pressure. Thus during the operation of the motor, the instantaneous movement of the armature under magnetic pull will not necessitate movement of the entire column of liquid between the supply tank and the recess C but only the small volume of liquid in the chamber F. This will be propelled by expansion of the air in the hollow cap I and will follow the diaphragm without development of high vacuum. However, the expansion of air originally in the cap J will reduce the pressure to below atmospheric and as the liquid in the supply tank is under atmospheric pressure this will cause a more gradual flow of liquid through the conduit to replace the liquid expelled from the chamber F. In other words, in place of a jerky action a smooth flow of the liquid is produced. The action of the spring 0 in lowering the diaphragm and expelling liquid from the recess C is not as instantaneous as the movement under magnetic pull. However this also would be more or less jerky in its action if it were not for the air chamber in the hollow cap K. This will permit a comparatively small volume of liquid first expelled from the recess C by the downward movement of the diaphragm to be forced into the hollow cap K compressing the air therein but relieving the high pressure on the liquid. The compressed air will gradually expell the liquid thus forced into the cap, and in this way will smooth the outward flow of liquid expelled by the pump.

Another very important advantage of the construction as above described is the increased .efliciency of the pump.

Comparative tests have shown that the pump which is not provided with air chambers J and K will not handle an equal quantity of fluid in the same length of time and with the same consumption of energy. Thus my improved construction may be used either to increase the capacity of the pump with the same current consumption or to obtain the same capacity with a decrease in current lcon sumption. The reason for this is that the air chambers relieve the maximum load on the motor in a portion of each cycle with more uniform distribution of the load throughout the cycle.

What I claim as my invention is:

A liquid fuel pump comprising an integral casing having an open top chamber therein with a recess in the bottom of said chamber and a pair of smaller diameter recesses in the bottom of the aforesaid recess, said integral casing also having fluid inlet and outlet passages respectively connected to said smaller diameter recesses, a flexible diaphragm covering said first mentioned recess, an annular hollow member clamping the marginal portion of said diaphragm to the bottom of said chamber, a coil spring housed Within said hollow member with one end abutting thereon and the opposite end bearing against said diaphragm to resiliently press the same into said recess, inlet and outlet valves located in said small diameter recesses, a closure for the open top of said chamber, a reciprocatory electric motor having the electromagnet thereof mounted on said closure and the armature within said chamber in operative relation to said magnet, said armature being also connected to said diaphragm to intermittently actuate the same outward against the resistance of said spring drawing fluid into said recess and also storing additional energy in the spring for expelling the fluid, hollow cap members mounted on said casing, which latter is provided with openings therein connected to the respective passages, each cap member covering one of said openings and forming an air cushion holding chamber being of a capacity at least equal to but not greatly in excess of the maximum displacement of said diaphragm in a single stroke thereof, and a flexible diaphragm separating the air from the liquid Within the chamber.

References Cited in the file of this patent UNITED STATES PATENTS Van Guilder Dec. 27, 1927 Schweisthal Feb. 16, 1932 Zubaty Jan. 23, 1934 Whitted Aug. 15, 1939 Whitted Aug. 15, 1939 Jencick May 20, 1941 Tabb June 30, 1942 OConnell Dec. 26, 1950 Robinson Jan. 13, 1953 Svenson Dec. 12, 1954 

